fix package.json

package.json

@@ -7,7 +7,7 @@
   "devDependencies": {
     "babel-cli": "^6.26.0",
     "babel-preset-env": "^1.6.0",
-    "babel-preset-stage-2": "^6.24.1"
+    "babel-preset-stage-2": "^6.24.1",
     "nodeunit": "^0.10.2",
     "rimraf": "^2.6.1"
   },